1. Field of the Invention
Embodiments of the present invention generally relate to a thermal processing apparatus and method.
2. Description of the Related Art
The integrated circuit (IC) market is continually demanding greater memory capacity, faster switching speeds, and smaller feature sizes. One of the major steps the industry has taken to address these demands is to change from batch processing silicon substrates in large furnaces to single substrate processing in a small chamber.
During single substrate processing, the substrate may be heated to a high temperature to allow various chemical and physical reactions to take place in multiple IC devices defined in portions of the substrate. Of particular interest, favorable electrical performance of the IC devices may require implanted regions to be annealed. Annealing recreates a crystalline structure from regions of the substrate that were previously made amorphous, and activates dopants by incorporating their atoms into the crystalline lattice of the substrate. Thermal processes such as annealing may require providing a relatively large amount of thermal energy to the substrate in a short amount of time, and then rapidly cooling the substrate to terminate the thermal process.
Dynamic surface annealing (DSA) techniques have been developed to anneal finite regions on the surface of the substrate to provide well-defined annealed and/or re-melted regions on the surface of the substrate. Generally, during such processes, various regions on the surface of the substrate are sequentially exposed to a desired amount of energy delivered from a light source to cause the preferential heating of desired regions of the substrate. These techniques are preferred over conventional processes that sweep the light source energy across the surface of the substrate because the overlap between adjacent scanned regions is strictly limited to the unused space between die, or “kurf,” lines, resulting in more uniform annealing across the desired regions of the substrate.
DSA techniques may utilize a single light source, such as a red laser having a wavelength of about 810 nm, and anneal the desired areas of the substrate. The red laser does not cover the entire spectrum of wavelengths and therefore may not achieve optimum annealing. Therefore, there is a need in the art for a DSA apparatus and method that can effectively anneal a substrate utilizing a greater portion of the spectrum of wavelengths.